Methods and apparatus for detecting azimuthal non-uniformity in a plasma processing system

摘要

Apparatus and methods for assessing RF return current azimuthal uniformity are disclosed. A plurality of non-linear substantially-enclosed RF current sensors are disposed azimuthally around a central axis of a plasma processing chamber. When a plasma is ignited in the plasma processing chamber, the RF return currents are sensed in the plurality of non-linear substantially-enclosed RF current sensors and analyzed to ascertain whether RF return current azimuthal uniformity is acceptable.

主权项

1. A plasma processing system having a plasma processing chamber, including a lower electrode assembly, comprising:
a plurality of RF straps to permit RF currents to traverse said plurality of RF straps; a plurality of sensors, each of said plurality of sensors being coupled with one of said plurality of straps, and each of said plurality of sensors has a first end and a second end separated by a gap to provide coupling with said one of said plurality of straps, wherein each sensor represents a non-linear substantially enclosed RF sensor; wherein said non-linear substantially enclosed RF sensor is coupled to a co-axial cable, a sheath of said co-axial cable is coupled to a first portion of said non-linear substantially enclosed RF sensor and a core of said co-axial cable is coupled to a second portion of said non-linear substantially enclosed RF sensor to acquire voltage measurements between said first portion and said second portion.